They could be anything from spam offering male enhancement to furtive exchanges of political strategy with convicted lobbyists, but observers say the White House deleted more than twice as many e-mails as previous estimates, bringing the total number of missing communications involving administration aides like Karl Rove and others to higher than 10 million.

Anne Weismann, the top lawyer for a watchdog group suing the White House, said sources close to Congressional and private investigations doubled previous estimates of the number of deleted e-mails.

"I will tell you, by the way, that it's way higher than five million," Weismann, chief counsel for Citizens for Responsibility and Ethics in Washington told ChannelWeb. "It's more than 10 million."

CREW and another open-government watchdog, the National Security Archive, have joined forces to force the government to restore the millions of e-mails that were improperly deleted.

Last month, the pair scored a legal victory in convincing a judge to order the White House to retain backup tapes that contain archived copies of the deleted e-mails. The Temporary Restraining Order required the Executive Office of the President to maintain copies of all the backup tapes it has, although CREW lawyers cannot say how many of the missing e-mails have been preserved for future historians.

"I have a sinking fear that the backups we want have been overwritten. Millions of e-mails, gone. Obviously, if they're already destroyed ..." she told the Web site, trailing off.